Weathering 🌡️ Flashcards
(14 cards)
What is weathering
Weathering is the process that breaks down rocks into smaller pieces over time. It occurs in place, meaning the rocks are broken down where they are
Two types of weathering
Chemical
Mechanical
What is chemical weathering
Rocks are gradually dissolved or altered due to chemical reactions, often involving water and gases like carbon dioxide
What is mechanical weathering
Rocks are physically broken apart without changing their chemical composition.
What is freeze thaw action
Freeze-thaw action is a type of mechanical weathering that occurs when water enters cracks in rocks, freezes, and then thaws, causing the rock to break apart.
Explain freeze thaw action
During the day, rainwater collects in the cracks or joints of rocks.
At night, when temperatures drop below freezing, the water in the cracks freezes and expands by about 10%.
This expansion puts pressure on the surrounding rock, widening the cracks.
When the water thaws, it settles deeper into the joints, repeating the process.
Over time, the repeated freezing and thawing cause pieces of rock to break off. These loose pieces are called scree and often accumulate at the base of slopes, such as those found on the Great Sugarloaf in Co. Wicklow.
In freeze thaw action how much the cracks explain by
About 10 percent of
What is carbonation
Carbonation is a chemical weathering process where rocks, particularly limestone, are dissolved by carbonic acid.
Explain carbonation
As rainwater passes through the atmosphere, it absorbs carbon dioxide, forming a weak acid known as carbonic acid.
When this acid rain falls on limestone, it reacts with the calcium carbonate in the rock, dissolving it. This creates deep cracks called grikes and flat slabs called clints, forming a unique limestone pavement.
Over time, the acid weakens and erodes the limestone, sometimes creating features like swallow holes where rivers disappear underground, and caves as the river erodes the rock below the surface.
Because limestone is permeable, water continues to move through the rock, dissolving more material and enlarging the joints and bedding planes. This can lead to the formation of stalactites and stalagmites in caves as dissolved limestone is deposited
Is limestone permeable
Yes
What is a pillar
When a stalactite and stalagmite grow until they meet, they form a pillar.
What are stalagmites
Thick columns of calcite that build up from the floor of a cave, directly beneath stalactites
What are stalagtites
These are slender columns of calcite that hang from the ceiling of a cave
Where can the underground limestone features be found
The burren Co Clare
